A. Field of the Invention
This invention relates to travelers useful in ring spinning of staple into yarn. More particularly, the invention relates to specially designed travelers which permit ring spinning frames to be operated under conditions that provide low twist yarn of increased bulk at higher yarn throughputs (productivity) than is otherwise possible using conventional travelers.
B. Description of the Prior Art
Carpet staple in the form of sliver (a loosely assembled strand of staple fibers without twist) is coverted to useful yarn on ring spinning frames. The frames consist of a plurality of positions or stations each of which processes sliver. Each position comprises drafting rolls, a ring-and-traveler take-up mechanism, and a bobbin mounted on a rotatable spindle. The drafting of the sliver and the twisting and winding of the yarn onto the bobbin proceed sequentially and continuously. Travelers used in spinning carpet yarns are usually ear-shaped and range in weight from 3.0 grains (0.2 grams) for a 6's cotton count to 18.0 grains (1.2 grams) for a 11/2 cotton count. Conventionally, travelers used in spinning the coarser counts are not only heavier, but also taller and wider in cross-section. In commercial practice, ring spinning frames are operated under conditions which maximize the productivity of the frames. Such conditions include operating the spindle at its highest practical mechanical speed and then adjusting the peripheral speed of the delivery rolls so that just enough twist is inserted in the sliver to keep the winding tension from pulling the sliver apart before it can be would onto the bobbin. For example, under such conditions the spinning of a 21/2 cotton count staple yarn requires about 4.25 turns of twist per inch (167.3 turns per m) which corresponds to a processing speed of about 40 ypm (36.8 mpm). While a reduction in twist level in the yarn would improve the bulk of the yarn, such a reduction cannot be achieved on a conventional ring spinning frame without sacrificing productivity to a trade-off the industry is not willing to make.